The present invention relates in general to a keyless deadbolt lock engaging device for use in combination with a conventional deadbolt lock tumbler assembly, and pertains more particularly to a keyless engaging device which is biased to return to a position in which the device does not interfere with disengagement of the deadbolt by a key. The keyless engaging device of the present invention is an improvement over known locking devices as the biasing prevents the lock from binding up and thereby making disengagement of the deadbolt difficult.
Deadbolt locks have become common because of the added security which they provide. However, deadbolts have not become as convenient as other types of locks, for example automobile door locks and tubular style entryway door locks. These types of locks can be locked from the inside while exiting, thereby making it unnecessary to have the key in hand.
Several devices have been developed in an attempt to overcome the need for a key when engaging the deadbolt. However, each prior device has included one or more of the following design problems.
One of the most serious problems with prior deadbolt engaging devices is the tendency of the device to cause “binding” of the lock. Binding of the lock assembly not only makes disengagement of the lock becomes jammed. A lock could become jammed while someone is on the opposite side of the door from the device, therefor unable to manually manipulate the mechanism free. In addition, the force necessary to overcome binding of the lock accelerates wear of the internal mechanism.
U.S. Pat. No. 3,539,548 to Kendrick discloses a lock with a rotatable exterior ring. The ring is rotated to project the deadbolt, but cannot be retracted by a reverse rotation until the deadbolt is disengaged. Upon attempting to disengage the deadbolt with a key, the user would be hampered by the rotatable ring, which would bind up the deadbolt assembly.
U.S. Pat. No. 5,010,749 to Lin is another example of a device which creates a binding effect in the lock assembly. Further, as the Lin '749 design allows the rotatable ring to move freely in either direction, the user could become confused and unsure as to whether the bolt has been fully engaged.
A similar design in U.S. Pat. No. 5,186,030 to Lin has other disadvantages in addition to lock binding. First, the device is not reversible to accommodate both right and left handed doors. Supplying duplicate mirror image parts therefore becomes necessary.
Second, the Lin '030 device would allow water to enter and be trapped within the device, leading to corrosion and/or freezing of the mechanism.
Another disadvantage of prior devices is that some designs are dependent on the projection speed imparted by the user. In these designs, the deadbolt is often not fully projected, leaving the lock easily retracted without a key.
Still another disadvantage of prior devices is the complexity of the devices. The use of a large number of intricate parts makes these devices extremely complex and difficult to assemble, expensive to manufacture, and may require specialized tools. These locks may also require extensive hole cutting on the door to be fitted with the lock and device.
Accordingly, it is an object of the present invention to provide a keyless deadbolt lock engagement device which is biased to return the device to an original position to prevent binding of the lock.
It is another object of the present invention to provide a deadbolt engaging device from being jammed by incorrect rotation, and possibly trapping a person.
It is still another object of the present invention to provide a deadbolt engaging device whose keyless operation has the same feel to the user as when using a key, without an odd or binding feeling.
It is a further object of the present invention to provide a deadbolt engaging device which will not allow moisture to become trapped within the device, thereby preventing corrosion or freezing of the mechanism.
It is still a further object of the present invention to provide a deadbolt engaging device which does not depend on the rotation or projection speed by the user, thereby assuring complete engagement of the deadbolt at each use.
It is another object of the present invention to provide a design which is less susceptible to a blow from a hammer, a twisting force from a wrench or similar tool, or drilling of the lock, thereby increasing security.
It is still another object of the present invention to provide a device which fits in the standard deadbolt door cutout.
It is a further object of the present invention to provide a device which has the basic appearance of a conventional lock.
It is still a further object of the present invention to provide a device which is of simple construction, is relatively inexpensive, and has long lasting reliability.
It is another object of the present invention is to provide a device which is obvious in its operation, requires only one handed operation, and which has a positive stop to transmit to the operator that the bolt is fully projected.